How do you complete the square x squared plus 12x plus?

Answer 1

36.

1. You take the coefficient of x : = 12
2. Halve it : = 6
3. Then square it : = 36
4. Add it.

This gives x2 + 12x + 36 = (x + 6)2

The above method only works if the coefficient of x2 is 1. If it is not then the processs is slightly more complicated.